Atttomatic mtjsicajg rwstrtt m-ent



UNITED STATES PATENT OFFICE.

CHARLES F. sToDDARD; or NEW YORK, N'. Y., AssroNo'n To VAlirizrtront PIANO COMPANY. 0F NEW YORK, N. Y.. A Geuren/Arron" 0F NEW'IERSEY.

AUTOMATIC- MUSICAL INSTRUMENT.

Application led March 30, 1917, Serial No. 158,593. Reneived December 19, 1921.

To aZZ whom t may concern:

Be it known thatlrC-Hmmnsl. S'roDnARn, a citizen 4of the .United States of America, and a resident of the city of New York, in the county and State oi" New York, have invented an Improvement in Automatic Musical Instrumentsof which the following is a specification.

This invention relates Vto automatic means for playing musical instruments, such` as pianos, and pertains more particularly to means for governing and varying tone intensities.

Among other objects the invention provides apparatus'for varying the normal'p'res. sure of the main'source of'powver. Suchapparatus may be combined with expression governing and regulating mechanism which, if desired, may have the capacity for producing incremental changes -in playingy intensif' ties, for maintaining' uniformity of any given playing intensity Whether one or many notes are simultaneously' sounded, and for producing substantially continuous progressive changes in playing'intensities.

In the type of instrument to'which this invention may find its more general application, the pressure of the main source' ef power is usuallymaintained substantially constant, while variations in playirig inten? sities are generally obtainedbyvvaryingthe influence exerted upon the playing pneumatics by the constant pressure' ofthe main source of power, This is usually. accom plished through the agency 'of a; throttle valve which controls communication between the main source of power und the playing pneumatics.4

For illustration the accompanying drawings show onepracticable embodiment of the invention which employs suitable pneu-v matically governed devices in cooper-'ation with n piano action,but`obv1cusl. y the invention is suscreptibleof embodiment in various constructions otherth'a'n that particularly. shown and describedherein.. It will also appear that itV is not indispensable that the invention be used inthe particular combination herein shown' and described for illustration since its substantial advantages may exist in combination with other suitable mechanism.

The single figure of the drawings is a dia grammatic representation of-a typical player action with operating and governing means Specification of Letters Patent. Ptented Mar. 14, 1922.

Serial No. 523,588.

application and utility player pneumatic 1 .provided haring a sticker 2 .to act upon'awippen 3 and'thereby operate the .usual piano action as well understood in the art. A wind trunk 7 leads to a wind chest for the player' prieulriatics each of'Which l's' a secondary'valve 8 con'- trolledy' by a. primar "'.jfalv'e 9.o erated from a tracker' board T tlir'ough'a uctA 1'0'in the usual manner.

The. trunk `7 communicates wiith a regulated exhaust' chest 12; whi'chmaybe of any practica-hiefconstruction; A high exhaust che'st 14, arranged forcommuriication with chest' 12 may be" connected bya trunk 15 with any practicable source of pneumatic exhaust. 'such as an ill'ustiztti'vev 4pumping mechanism generally denoted', by 1,6.4

'ForI purposes@ illustration and explanation .theapparja'tus' o flthe drawings has `beenselected, Therein'the strik'er'pneumatics 1 arecafu's'ed t'o operate b 1 tlieiegiilated ex'- haust i'r'chest 12. In o'rl ertovary' the oper'- ation of the striker lpneumatijc'shi's reofulating exhaust Vmay be' variedt by. su'bjectlng'` itmore or less to'tlieinflrieeQof'the high `eirh'a'ust in ehestflft; 'For t-liis`specic'p,ur pose! 'aforesa''fla i12-fpClit' 3 O` cot'1flled'- by a tli'rottlepvalve 41's provided bfetil'fthe: high exhaust' chest' 14' andthe' regulated exhaust chest'1'2. f

This' valve 31 may-beopeatedf by any.' suitable moans; prferbly'by l'agpparjatuslof chegenengl character of that'herein illus'- trated'. VIn thifsfsL ecific'apparatus.the'stern 32 of :the-valve 31 ris connected `to a movable board3'3fof bellows apparatus presently described; 'saidA board' beingt flin ed at. 17. Such @mais 1las .aree-n1-5cpcie for' controlling' 'the' valvelfQQI# 4automat-V ically produces incrementaljch'anges'in play-V ing iritensitiie'sgisitperforms a" regulating function; that" is, it' maintains any' given playing intensity 'Whether o'ne or'many .n'otes be sounded and it' automatically produces continuously progressive'changes in playing intensities for' crescendo and diminuendo purposes. In addition t .the means for controlling playing intensities through' the agency" of' the valve'31` further: me'an's, to which this invention is more particularly directed, are pro'videdto control or vary the pressure of high exhaust and therebyI give the apparatus a further capacity for varying playing intensities.

Following a brief description of the apparatus actin through the` bellows board 33, the embodiment of the further means referred to will be described. As the description proceeds it will be obvious that the invention issnot dependent upon the specific details of construction, or the specic mode of'o'peration' of the apparatus herein described.

Assuming for the present that the pressure of the main .source of power is maintained substantially'uniform, thethree capacities of the apparatus acting throughrthe bellows board 33 will bebriely described in the sequence heretofore indicated. y Beneath the board 33 are three bellows 34, 35 andf36 which have their upper boards secured to the comlnnfmovable board 33 and their lower'boards secured tel aY fixed jplate 18.` 'Another'bellows 37 has its lower vbo'mdfsecured tothe movable'board 33f`and its'upper board toa stationary plate' 38. A condition of partial exhaust is maintained at all4 times in the bellows 37. as presently described. The de ree of exhaust in bellows 3T maybe varie 4but'for the present this capacity may-,beldisrvegarded and` the pressure within `the bellows acting upon 'the board 33 maybe -considered uniform. Thus, the pressurein the bellows 3T., being always less than atmospheric pressure, said bellows in efect exerts 1'continuously uniform upward ull on the board 33 contributing to controlJ the valve 31. V

Duets 40, 41 and42 enter res )ectively the bellows 34,35 and 36.V -Each iluct may be controlled by any'practicable valve mechanism to admit toits bellows either atmosplieric pressure, or reou'lated pressure from the chest 12; and regutlated pressure may he admitted to the bellows selectively while atmospheric pressure will be present in these bellows, if any, which do not contain regulated pressure. Another regulated pressure is present in any one or more of the bel-y lows 34, 35 and 36 the effect thereof is to produce a downward pull upon the board 33. Thisdow-nward pull is opposed by the upwardQpulllwhich results from the condition of partial exhaust in the'bellows 37 the two contributing tocontrol the valve 31. High exhaust in the chest 14 exerts some downward pressure upon the area of the valve 31 itself; and regulated pressure in the chest 13 exerts some upward pressure uponthearea of the valve.

, Since thev regulated pressure is usuallyr greater, it generally predominates and the resultant upon the valve itself is an upward pressure which combines with the resultant of the pressure in the `several bellows to complete .the control 4ot' the valve 31.

The construction and` arrangement of the apparatus may be 4such that the opposed upward and downward acting forces control the valve and tend to hold it in a balanced condition. For example, if lregulated pressure be present in all three of the bellows 34, 35 and 36, the downward pull of these bellows upon the board 33 is at its maximum and tends to close the valve 31 and minimize the opening between the chests 12 and 14. Under these circumstances-playing'intensities, as controlled by this portion of apparatus, will be at the minimum.y The bellows 34, 35 and 36 will then operate substantially as a single regulator pneumatic for maintaining a uniformv degree of exhaust in the regulated pressure chest whether one or -many notes are concurrently sounded. A substantial uniformity of'plaing intensities will thereby be maintains; l' i The bellows 34, 35 and' 36 may be governed to vary playing intensities'by "varying Vthe downward .aeti" "force which they contribute to the contil 'of valve 31.L If atmosphere be admitted to the bellow/e36, for example, the aggregate pull on the board 33 is relaxed to some extent. To restorethe condition of balance the degreeof re ulated exhaust acting fupon the board 33 tirough bellows 34 and 35 will be permitteidjto Vincrease. Therefore the apparatus will operate to regulate playing intensities at a higher level. 4 Regulated pressure or atmosphere may be admitted to the several bellows 34, 35l and 3G selectively or in combination. To those skilled in the art, it will be readily k.understood that several well defined grades ot playing intensity may` thereby b ey established.

Upon admitting atmosphere to all the bellows 34, 35 and 36, the forces actin upward upon the valve 31 will so far pre ominate as to openthe valve to enlarge communication between the chests 12 and 14 to the maximum. l

Any suitable mea-ns may be adopted to govern that part of the vregulatin --nechanism which operates through bellows 34, 35 and 3G to initiate different substantially distinct grades of regulation. Herein the duct 40 connects the bellows `34with a valve chamber having a port vto atmosphere and a port to a chamber which is connected to the regulated pressure chest 12 through a passao'efly. A duplex -valve 51 is mounted in valvel chamber 5() and is eentrolled by a diaphragm 52 of a diaphragm chamber 53. A duct ,5 4 leads from said diaphragm chamber to avent Ain the tracker T correspondingly numbered. `The parts 50-55 described in connection with duct 4() are triplicated for ducts 41 and 42, the corresponding parts of the valve mechanism for the latter being indicated by the numerals 50, 51, etc.. with indices a for the valve mechanism for duct 41, and b for the valve mechanism for valve 42'.

The manner in which the: valves 51, 51- and 511 may be controlled from the tracker will be sufiiciently obvious to those skilled in the art so that. a detailed. description is' by which substantiallyV distinct grades 0II may be: estabdegrees of regulated exhaust lished for playing notes at substantially distinct grades ofintensity. In an apparatus of the'character described, -itis preferablel that the upward puli- 'on theboard`33 be maintained substantially uniform. For this pnurposc the preferred embodiment of the apparatus utilizes a pneumatic'system, about to be described, which exerts a pneumaticA pull through thebellows 37 in opposition tothe bellows 34, 35 and 36'; said'pneurnaticl pull' being maintained substantially uniform and corrected Ywhen necessary. For convenience in that part fof the descriptiony imf mediately -following;the :capacity -of theapparatus to producenincrementall changes inplaying intensities ma' bedisregarded and it may be assumed t at regulated exhaustis present in'alli the 'bellowsr34, 35 and awiththe result of' a maximum downward pressure -on the board 33. and' valve 31.

The bellows 37 is connectedffby duct 100 Witha pneumatic 101. A spring1102 is fastened to therm'ovablel board lof `pneumatic 101 and to an adjustable screw -103 threaded in a.block 104.' A @stop 105-S'.proyded t0 limit theezrpandng movement of the pneu matic 101. i The: pneumatic y101 .may be 'exhausted through a duct 106,0pening'to a 'valve1cham-- ber 104 having a port 109 to atmosphere and a port 110 to an exhaust chamber 111, pref erably connected tohigh: exhaust. A valve 1121is mountedlin chamber 107 and is controlled by a-diaphragm-113 of a diaphragm chamber 114; Diaphragm chamber 114 may be: exhausted through a bleed '115A4 and atmosphere maybe admitted thereto-through a duct 11G and port 117. The opening ofthe port 117 is controlled by a valve' 118 and as will be readily understood the effective opening of this port relatively to 4the' size of the exhaust bleed 115'will kcontrol the operation of the diaphragm 113 and valve 112, which in turn controls the degree of exhaust in pneumatic 101 and bellows.

Communication between the pneumatic 101 and valve chamber 10T through duct' 106 is somewhat restricted by an adjustable screw 119 which slightly retards the action of the valve 112 upon the pneumatic 101. Upon a slight fluctuation in the degree of exhaust in the pneumatic 101 the valve 112 is automatically operated, as hereinafter described, to restore, thereby in effect maintaining, the degree of exhaust the same substantially uniform. This restoration will be sli htly retarded and rendered more delicate and refined because of the intel-position of theobstruction screw 119.

For the purpose of more rapidly restoring the intended normal pneumatic condition of pneumatic 101, a second adjustable obstructhevalve chamber 107 and the pneumatic 101y anda by-puss around the screw 119 is provided by passages 121 and 122. lVhen it is desired to compensate for an extremeluctuation in the pneumatic condition of pneumatic 101 the by-pass 121-122 may be opened. y-pass 121-122 maybe closed by a-valve 123 mounted upon a diaphragm of a. diaphragm chamber 1211. This chamber is connected by a duct 125 with a valve cham-- ber126 having a port 127 to atmosphere and a port 128 to exhaust chamber 111. A valve 129 controls ports127 and 128. Normally valve 129 is seated to close exhaust port 128 and open atmosphere port 127` thereby admitting atmosphere to duct 125 and diaphragm chamber 124. This permits valve 123 to be normally'seated to close by-pass 121. Upon an extreme fluctuation of the pneumatic condition in the pneumatic 101, the valve 129 is automatically lifted to exhansb-diaphragm chamber 124 and open bypass121-122, thus permitting a more rapid flow of-air-alongduct 106.

VThe-valve 129` is governed by diaphragm 130 ofa diaphragm chamber 131 which communicates by aV duct 132 with a port 133 adjacent the port 117, the port 133 being controllediby,v the valvef118. The usual exhaust bleedffor ldiaphragm chamber 131 is provided byr a bleed. passage 134.

'.Ihe'valvelll is=operated by an arm 13T projecting -fronithe movable board of the pneumatic 101 andisrso'arranged that the port 11? fwill-:be first opened to operate valve 112 and thereby correct4 a variation in the pneumatic condition of pneumatic 101. Only thereafter if the expansion of the pneumatic 101 is suliciently great, will port 133 be opened to cause a more rapid correction. of the intended normal pneumatic condition.

The pneumatici101 is controlled in its movements by the differential between the pull ot the spring 102 and the action of the exhaust within the pneumatic. lVith the described arrangement of valves, these opposed forces tend to hold the pneumatic 101 in balance. For example. the pneumatictends to collapse to that point at which the atmosphere bleed 117 is maintained at such acapacity that the degree of exhaust in the diaphragm chamber 114 holds the valve 112 in that position in which the relative exhaust and admission of atmosphere past the valve 112 ydetermines a degree of exhaust within the pneumatic 101 which just balances thepull of the spring 102. Any influence tending to disturb this condition of balancewill be promptly compensated so that the ultimate effect is to maintain within the regulator tension system a substantially uniform degree of exhaust which, as will appear to those skilled in the art, will 'be determinedulitmat-ely by whatever tension may be given to the spring 102 by its original adjustment.4 .The mechanism which intervenes between? said spring and the regulating pneumatics eiiectually eliminates theobjections to `the use of a mechaniealspringandserves to transmit? thefaction of said spring in such a ywayas to refine the re ulatioir and render itl extremelyV accurate. it ispreferred that the effective area o the pneumatic I101 be somewhat greater than that of bellows 37 so that the expanding iandv Y collapsing .movements of the pneumatic-.101

(in responsev to similar movements -oi' the bellows 37) are much `lessdn extent. With such `an arrangement the minimized more; ments r' of. the. pneumatic 101 produce vonly slight elongations and contractions voli the: spring 102 and-therefore produce only minimum changes in the tension ofthe spring.

lTliat part of the apparatusjust described.Y in addition to its capacity for maintaining substantial unormity oil-tension upon the regulator pneumatic (herein exemplified, byv

bellows 34, 35 and 86,) also possesses the capacity Vof varying playing intensities by varying the upward pull ony the .regulator and of controlling this variation l at diii'erentl in detail herein.

speeds.; r i i 'I Ifthe pneumatic 101 A'is collapsed=beyond its position of normal self-adjustment Athe spring 102 will he elongated, .thereby increasing its tension andfcausingan accompanying increasein tension of t 1e air condition in :pneumatic 101 and bellows 37. This will result if the valve 112 is raised and held in raisedposition for a substantial length of time, that is, until the pneumatic 101 is completelycollapsed. Air will be withdrawn from pneumatic 101 through the samll opening formed by the obstruction screw 119l and an increase in tension will therefore take place at a relatively slow speed.

This operation of the 'pneumatic 101Aultimately causes a slow increase on the upward pull of the movable board 33 and such a variation of one of the forces controlling the valve 31 causes a slow continuously pro-l gressive increase in playing intensities.

1f the valve 112 is lowered to close port i urtlierrnore,4

110 and 'open port 109, atmosphere will be admitted to pneumatic 101 past obstruction screw 119 and permit a slow restoration oi expand.: -these two operations result re-V spectively 1n a' fast, l.continuously progres-y siveafincreaseff. or decrease rplaying 1n= 1 Such jchangesin playing intensities as are describedi in the preceding vpara raphs are commonly .termed crescendo and minuendo effectsfl or lniir'f- The above* descri deo'perations .of the valves 112 :and-1291011 apro ducin crescendos and'diminuendos. mayfbel contro led by any practicable means. For illustratiomfthe dia phragm chamber-2 114 imay 4be connected tto thetraclre1- by -awd'uctl .opening rtcl `n tracker "vent lcorrespondingly numbered which `.may be opened or closed tby perforations 1n a-music sheet.` The diaphragm chamber llfmayf-be similarly connected to the trackeribar by-a duct 139.== As will bev readilyfunderstood b those skilled in the art the' regulating mec anism may thus automatically produce fzcresc'endos -andj diminuendos iat different speeds under the Acontrol of-a note sheet-"wwf ff- '.i -f f -A The manner of r perly coordinating the several partsaof t e' regulating mechanism' under l:the 'control-z ofl a` perforated music sheet willr fbelsuiciently 4"obvious tothose' skilled in' the art-and-need not :be described The A apparatus heretofore ideseribed provides means 'orvyincreasing z-playing intensities'from a. redetermined minimum to afmaximuinwluch is adependent upon the pressure establishediat-the main source of power. In other words,speceally referring to the apparatus'heretoforedescribed, the valve 31 may be controlled to increase Vthe degree of exhaustv in chest; 12 vbysubstantially distinct increments or byv substantially continuous progression at-` different i speeds, maintaining all the fwhile uniformity o playing intensities whether one or many notes are concurrently sounded. i

It is oftentimes desirable-in the type of instr umentto-whichthis,invention more particularly relates, that-is to say, an instrument adapted for the mechanical reproduction of the manual renditions of skilled pianists, to have available for use from time toytime a greater force for the operation of crates through bellows "board? 33.

the player pneumatics than it wouldvbe advantageous or desirable tomaintain Acontinuously in the mechanism. The continuous maintenance by the pumping mechanism of the highest pressure which Acould be advantageously used, might eventuallyweaken the instrument and result in a more or less seriousimpairment of its accuracy and refinement of operation.

When producing theV finer shades of intensityA changes du-ring'the playing of -a composition With pianissimo eli'ect, renements of operation can be more eifectively obtained it the difference between the `pressure of high exhaust vand the pressure o= re llatedfexhaust is not too great. During ie playing of notes with pianissimo eifect a very slight variation in the de ree of regulated Vexhaust is immediately noticeable in the playing intensities, and therefore at Such ltimes the apparatus may be adjusted toroduce smal-ler increments of change.- Asst-lie .reproduction of a composition approaches lfortissimo-efiect, sli ht changes inthe degree of regulated ex aust are, not 'as noticeablef- Therefore, to produce an audible' '.vanizationfduring fortissimo playing greaterchwnges must be made inv the degree oregu-lated exhaust. Furthermore it will' be readily. understood that the effectiveness of the reproduction 4of a composition depends to a .great extent upon the contrastbetweem the lowestand highest. playing intensities which may be inaugurated by the pressure; governing apparatus.. .l

lVithzthese and other factsin mind, means are herein provided for automatically increasing the-degree: ci `exhaust maintained by the main-source olf-:powers Iif and when itis desired-to havela 'greater-power available ,for the-operation of: the striker pneumatics. The' specific vapparatus-embodying `this invention which-is1herein shown for purposesf of. zillustration;I :will be! presently described and: it is preferably. ,though not essentially.; madef dependentpfupon the rai'n expression governing mechanism which opyMeans nialv also be provided for manually or automatically rendering thei pi'esent'lv described apparatus continuously inoperative 'or placing. it in readiness for operationn-'hen condi-- tions requires. n i

Referring again tofthednawi'ngsi, the'main source fof powerll," Which'may'be of any preferred. constructiomzis herein.- Villustrated as a ,number ofzexhauster bellowsV 3005 arranged radially about agshaft'. V3014 which is journalled in'suitable bearings within a casing 302. A drive wheel 303-is fast to the shaft 301 and the pumping mechanism is preterably operated from an electric motor M through a belt 304. VA crank arm 305 is tast to the shaft 301, and concentrically journalled upon a crank piu 306, are connecting contributes to control. the valve,

rods 307 which, at their opposite ends. are journalled to the movable boards 308 of the respective exhauster bellows 300. Each bellows 300 is provided with inlet ports 309, which open to a ycommon Wind chest 310 and are controlled by flap valves 311. Outlet ports 312 are formeel in the movable boards of the exhauster bellows, and are controlled by iap valves 313. v

A governor or reservoir bellows 351 is placed in communication with-the high exhaust chest 14 conveniently through wind trunk 151 wind chest 310 and a port 350. This bellows has a movable board 352 and a stationary board 353. A spring 354- is at tached to the movable board and at its other end is fast to an adjusting screw 355 threaded in a bracket 356.

An atmosphere port 35T is provided for the reservoir bellows and preferably located in' the movable board 352. A valve 358 commonl)v called a spill-valve, mounted upon a threaded stem 359 and conveniently held in position by arms 360 and 361, is adapted-to open or close the port 35T as occasionv may require, A light spring-.362 contributes to hold the valve in closed position. During the operation oi the reservoir bellows the differential between atmospheric pressure on the outside of the valve and the pressure of exhaust upon the inside of the valve, also `The resultant force tends to hold the-valve in 'closed position.

The pumping mechanism is driven at a substanially constant speed and therefore has the capacity7 forexhausting air from-the .wind chest 310 at a' substantially constant speed. Air may low into th'e chest 3l0froni two general sources, (1) from the playermechnnisur( including all parts of the instrument which are. required to b'eaoperated by withdrawing air therefrom for decreasin the pressurevof-the 'contained air) and', (2 through the reservoir bellows 351.4 It is ob` .viously immaterial towhat part of the apparatus the-reservoir bellows v1s connected,

because its operation and eii'ect will be substantially the same if connected to any part of the high exhaust system between the throttle valve 31 andV the .pumping mechanism.

AThe amount of air drawn 4from the player mechanism generally varies from time to time according to the amount of atmosphere admitted during the operation of the instrument. If means are provided for admitting atmosphere from another source (herein exemplified by the spill-valve' inthe reservoir bellows) this second source of atmosphere may' be automatically varied tc compensate such variations and make up with the air drawn through the player lmechanism substantially' the full capacity of the pumping mechanism` By suitablemeans, hereinafter illustrated, the second source of air may be to expand somewhat thereby closing more so controlled that it will admit atmosphere or less the spill-valve 358 and decreasing the only when a predetermined tension has been amount of atmosphere admitted through attained in the high exhaust system and will port 357. In this manner, as will be underthereaiter maintain a substantially const aut stood by those skilled in the art, the reservoir degree of tension therein. lf the action of bellows maintains a substantially constant the atmosphere port or spill-valve is varied tension on high exhaust, the opening of atthe tension throughout the high exhaust sysinospliere port 357 being automatically tom may also be vnriedvaried as required. Furthermore it will also Ordinarily a variation in the degree of be readily Aunderstood that the tension of Vhigh exhaust will have slight eii'ect upon high exhaust determinable by the reservoir regulated exhaust and upon playing intensi- 0r governor bellows is dependent upon the ties in vien1 of the fact that the pressure of `tension of the spring 354. F or convenience high exhaust upon the upper side of regu- .the tension so governed may be termed the -lator valveA is a relative] y Small .fm-,toy n the normal minimum degree of exhaust main- 8o balancing equation controlling that valve. tained by tliemain. source of power.

lf, however, the degree of regulated exhaust T hisl normal minimum tension of high-exis caused to approximate the normal degree haust 1s preferably adjustable and adjust- 'of high exhaust by opening the regulator ment may herein be made through the exhaust may be effective to vary playing by varying the length of the-:spill-valve intensities. Y stem 359 by :turning the valve on the threaded Disregarding for the moment the'c'apacity portion' ofitsstemA to cause. the valve to of the apparatus to vary the degree of high operate when themovable board is nearer the exhaust, the manner in which high exhaust abutment for va higher tensiom or further-,90

valve to its full eapacitva variation in high spring 4354 by means othe screw 355, or

is overned to maintain a normal substanawa Vfrom the abutment for a lower tension.

tia ly uniform pressure will be first de- 'ln either case the ultimate adjustment of the scribed.v tension of high exhaust is dependent upon The capacity of thepuniping mechanism ythe tension o' ,the spring acting upon the for exhausting air from the player mecharSrVOlr." 95 nism is generally sufficient lto predominate The manner in whichthe desired normal over any normally possible admission of air minimum tension may `be maintained thereto. Therefore the reservoir bellows throughout the hi h exhaust system having will be partially exhausted. The diiierenbeen -suiliciently escribed'; the manner in tial between atmospheric ypressure acting which the specific illustrative apparatus may upon-the outer Asurface of the movable board vary the tension of high exhaust Amay now 352 and the pressure withinthe bellows will be considered: 1 I A cause the reservoir bellows to collapse some- It has been assumed for lconvenience in what and thereby elongate' and tension the describing the manner in whichthe normal spring 354. As the reservoi bellows colminimum tensiono high exhaust is mainlapses the stem 359 of the spill-valve 358 will tained that the abutment 363 comprising. the

contact with an .abutment 363,herein shown movable board of-pneumatic 364 is station- -out the high exhaust system.

as the movable'board of a'pneumatic 364, ary and immovable. 4It is` preferably Assuming that the abutment 363 is fixed, the through the agency of this pneumatic 364 spill-valve 358 will be opened more o1' less and its capacity for moving the abutment lio to admit atmosphere to the reservoir bellows 363 that the tension of high exhaust is vaas required to maintain the movable board -ried when it` is desired to have a greater 352 in a substantially stable position at a tension available for operating the playing point where the spring 354 is somewhat elonpneumatics.

gated. Under these circumstances the ten- The interior of the pneumatic 364 is consion of the spring 354 will govern the denected with a source o exhaust, preferably gree of exhaust within the reservoir belregulated exhaust iii the chest 12.` There lows and consequently the tension throughmay be interposed in this connection a valve mechanism for opening the pneumatic 364 When substantially no air is being admitto atmos here if and when it is desired to 120 ted to the chamber 310 fromthe player Yrender t e pneumatic entirely inoperative mechanism, the spill-valve '358= will be except as a fixed abutment. A. duct 365 opened widely to permit substantially the 'leads from the pneumatic 364 to a valve entire amount of air exhausted by'thepumpchamber 366having a port 367 to atmosin mechanism to be drawn througlrthe port phere, and a port 368 to an exhaust chamber 35 the reservoir bellows 351 and port 350. 369. A duct 370 connects exhaust chamber lf the amount of'fatmosphere admitted 369' with the regulated pressure chest 12. through 'the 4playing mechanism increases, A valve 371 is mounted in the valve chamber the tension of high exhaust may decrease 366 and is controlled by a diaphragm 372 of slightly and permit the reservoir bellows 351 a diaphragm chamber 2373. The diaphragm 130 chamber 373 has a port 374 to atmosphere and is provided with the usual bleed passage to the exhaust chamber 369. Any suitable valve such as u slide valve 375 may be provided to control the atmosphere port 374. The diaphragm chamber 3T3 muy also be connected if desired, `by a duct 376 with a veut in the tracker' bar correspondingly numbered. A stop 377 may be lprovided. to limit the expanding movement of the bellows 364.

Assuming that atmosphere is present in the bellows 364 the position of the movable board 363 will be controlled by the differential between the pressure of atmosphere acting upon its inner surface, and the pressure of high exhaust acting upon its outer surface. The resultant will be a force tending to hold the movable board 363 firmly against the stop 377. The differential between atmospheric pressure acting upon the outside of valve 358 and the`pressure of h'i h exhaust acting upon the Ainner surface o? the valve plus the very light tension :of the spring 362, tends to hold the spill-valve B58 in fixed relation with the atmosphere port 357 As the reservoir bellows collapses the stem 359 will impinge upon the movable board 363 of the pneumatic364 and theresultant .of the forces tending to-close the spill-valve will be opposed by the force tending to'hcld the movable board 363 in fixed position. The area of the movable 'board 363 may be so related to the areafof the yspillvalve and the tension of the-spring 362 that the force tending to hold the pneumatic 364 in an expandedposition will entirely overcome the force tendingto collapse the. penumatic. Iny this mannen'when atmosphere 1s" presentin the pneumatic 364, the movable board l363,-orms to all intents and purposes, a fixed abutment, andin the manner-previously described the normal minimum tensionofhigh exhaust willV be maintained with substantial uniformity.`

To vary the norma-l minimum tensionV of high exhaust theoperation of the spill-valve may be so controlled that it will not-open to admit atmosphere through port 35.7 until a higher degree of exhaust has been vattained within the reservoir bellows. This may be conveniently accomplishedby permitting the reservoir bellows to collapse to a' greater extent before the spill-valve is opened thereby increasing indirectly the tensionY onY the spring. For .this purpose, the position of the abutment 363 may be changed, preferably by means presentl described.y

If the movab e boar-d 363 of pneumatic 364 is drawn away from its stop 377, the reservoir bellows will of necessity collapse to a greater extent before the spill-valveis opened to arrest its collapse. The spring 354 will thereby be elongated, to increase the force tending to expand the reservoir bellows. The increased spring tension will govern a correspondin increase in the degree of exhaust within t e reservoir bellows.

Any suitable means may be provided for appropriately moving the abutment of the board 363 of the pneumatic 364. Herein the pneumatic 364 is adapted to be exhausted to a greater or lesser degree through a connection with any suitable source of exhaust, preferably the regulated pressure chest 12. The regulated exhaust chest may be placed in permanent communication with. pneumatic 364 by opening atmosphere port 374 in the interposed valve mechanism and the consequent raising of the valve 371 by the action of regulated exhaust upon the diaphragm 32.

VUnder the control of the bellows board 33 and the Aregulating mechanism acting therethrou h, the degree of regulated exhaust may e varied froma minimum which is onlysufficient` to soundnotes with minimum intensity to .a point where the degree ofregulated exhaust will Vclosely approximatef or equaltha-t of highzexhaust. Under :such conditions the valve 31 may be opened to restrict only topa veryl slight degree, it' at all.' the communication vbetween high exhaust chest 14 and regulated exhaust chest vl2. ,The differential between the degree of .exhaust within the pneumatic 364 and that within the reservoir bellows 351. will be gradually decreased by t'heincrease in regulated exhaust .andA asiV the degree of regulatedexhaust more nearly ,approximates the degree of high exhaust the abutment 363 will foppose with af gradually diminishing force, the force exertedthroughA the valve stem 359 ofthe. spill-valve 358.- The' area ot' the pneumatic'364 may beso related to thearea ofthe valve. 358 that the forces acting upon the abutment 363: and. tending to move it toward its stop, will .predominate Vuntil the degreefof regulated exhaust nearly-equals that ofhigh exhaust. The-opposing force may then gradually :overcome Vthe `force tendingA -tohold the pneumatic 364 in expanded position and in-augurate a collapsing move'.- rnent of the pneumatic364 to permit the iescrvoir bellowslf to collapse to a greater extent .before the spill-valve opens, thereby increasing the tensionon the spring, 354. This` as heretofore explained, lwill govern an increase in the tensionV of high. exhaust throughout the high exhaust system.

'This increase in the deg-ree of high exhaust acting uponthe regulator valve may, even if the valve'isnot wilde open, slightly increase the degree of regulated exhaust, and such an increase being communica-ted to pneumatic 364i will decrease the differential between the pressures of regulated and hicfh exhaust acting upon opposite sides of tlie abutment 363. The initial increase in high exhaust will also increase the differential between the pressures of high exhaust and atmosphere acting upon opposite sides ot valve ual 358l and 'temi-V 't'o increase-the :force with which the steluilfharsagainst the .abutnl'ent- 363; :Under these circumstanees a Continuously progrossivecolla])se ot thelpneuvmatic 364 may' 'be-#inaugurated govern la continuously progressi-ve increase ottension in the high exhastsystemv 'lf' f Assume fordthe purposejiof:illustration, thatlunderj'the control1 offthat )art "of'the -regulatingl mechanism gaeting 4t rough bell flo\vs 34,j35"and 36, fitxi's desired 4to operate the striker "pneumatics` by' regulated exhaust at a "tensionA nearly approximating high exhaust. 1For i this 'purpose atmospherermay -b'eadmittecl to bellows '34 and 35'wl`1ile reglulate'd fexliust- 'is presentonly i inffbellws '36; lfils previously described this A:results n relaxing the downward pull upon Ethe' board 133 and establishin ia balaneingfequationiffoi' -th'eieolitrol of valve' 31"whiellf will opelf'ate to maintains? la A'iig 4'-intensti'es 'atffaf-relfatively hivhjileve .i LXlithf'the'degree lofi'regulated exhaust so' maintained'thef'balanee1o forces 'tending to! ihold abutment2 363i against?" i its stop is disturbed," anjd a'eollapsing movement Vof thepneumatic' 364-islinauguratedl This results in aninerease'in the tensionof'high exhaust inthe' chest 1li above-the' `uniform nor'z'na'l minimum; HfThe pressure' of highI ex; hau's't on 'the uppeifsidei -ofrthe1valve 3Icon stitutingiaaet'or i in fthe; ba'laeingj quation controlling valve 31;` the increase 1n illiglrexfhaustfinauguratedf by the` described increase in 4fre'gulatedf 'exhaust Twill tend .1 `'to iestablish -anew balancing equationtorgovern a further sli ht fincrease;inl-thetension of regulated eX aust.'i'1 `hel action "just f'tlescribed'majr 'continue luntil i rthe pniunatie- 364 1 is oompletel'ycollapsedfand the degree' ofhhighI exhaust'inoreasedto itsfmaxmunr f 1 1' The 'described lIinpxea'se' in the degree of high'exhaust may 'or may-inotfprocluce an increase in'fre ulated earlial'istisufloient to cause an* audib e variation girr Aplaying f intenstiesfdependin upon the size of the regu'- la'tor valve 'an the-relative value of-the force l of` high'A exhaust in the 'regulating 'ballancingequation.'3 Obviously, ifatmosphere is admitted to bellows`34, '35 and 36 ofthe regulating mechanism' and `thelvalvej 31 thereb '0 en ed wide,'regulated exhaust will gig lexhaust'and the maximumpower o the instrument berenderedava'ilable for operating the' 'playing pneumatica" Under such -e'ijreumstanees"Y any purely regulating functions necessary to loeE performed f may be transferlfe'dfom the jvalveBhto the reservbir"liello ws" 351 which w ill1'tl1en maintain iegulat'e g exhaustsubstantialljf uniform as itjreviously maintaine high exhaust 'unil forni i a nd insure the maintenance of luur formity of playing'fwhether one 'or many notesfare'soundedconcurrently;l l For* further 1illustration', assume that through the ageneybtthat' part Vof "the reg` regulatdpressure in these! bellows al'ecting merely lthe' pontsin the scale i of yintensities at wirhaehf thexsre'seendogoperation 1 e'ommences. Trefreabljr'the bellows 37 ssoproport-ion'erl that xther:pullfxeted`t'helrethrbu h1* will predomnate-o-ver 'the pull fexrted l't rough any :one: benl-l ofi the =bellows'34,f351andg 361 w: n' JP l ilring'gthe "igraduall increase r in regulated exhaust! veune'dl Eby 'that inci'easedtmpward 'pulh jthrough:-bell ws 237i :the differential 'betvveenffthe lpressures actig Iupon` 1 opposite sides :fof abutmentf'l 363ifw11l2 i b gradually ydiminishel:until- Fa' -eollapsing moven'ient of pneumatici 3640i?, i started, 'a's in :the Tease of regulattdfv exhaust finerease described-in oonne'ctienwith bellows 34;-'35' anti 36. :.When the-.degree .:of rei1lated-eadfausthas been buflieientlf irlerea edthetdegre 'of -high Aexhaust; mi lffbefaincveas'ed .wasn previously desribedtin'd)eventuallymvhenthe regulating valvenl gis .openetl suieently tY mise regulatedfexhaust'toi a pr'oximateuor equal the normal i xriinimiiin egee ofhiglij exhaust the latter will: heI nCL-'eaedvto-its maximum andi :correspondingly@increase'regulated fex lhaust; a fthe'ebyl 9i rendering u, thi fu'laximum power 'o f i' the Ainstrument 1a-vai'la'blefor a op-` eratingsthefpla p'neumatessim i x i '.The'= reverse peraion' fbfy- :Avihicl playing intensities aref ailovi'eed iand the?l degreeof high exhaust returnecli'tothe `normal yminiyinum elw-ill bea su'ilcentlyf '.clea'r' to those skilled' in tlie lart :twobviatei the y-Iieces'sity of|a-gletaleiiliidesezfphinitfrim .w-

4f y lt 'willbe'mbsrvedf from l theff fforeg'oing 'deseription' that' -ivhen' the 'regulaling mechanismf op'eliting'l -throfuglrVlr valve 131 vesta-bh lishes f a .I degree' 'o'f== regulated exhaust" approaehingi the1no1'm'alfaminmu'rn Edegree of high exhaustAf-the apparatus rjust"df'ascribed providesnieans for rendering available a greater .tensionl r fofffhigh F exhaust-`f Asy cle scribed; this; nays-be aceompl-ishe'dwautomatically "heneveb'thbf'mcreasefis'desirable5 without the fne'oes's'it'yl foffaax'liial lor vtracker controlazi fif- ;-i; fr if' ri 4- I i If desired tll'e'ffapparatusi forinereasing the' normal minimum? 'rtension ofjhigh' f eX- haust ina @be i renamed/inoperative by the closing portj '374 byslide' valve 'l 37 5. 'The diaphragm `o'hambe-r- 373 .-w'ouldfthen-be exhausted th'roughits bleed passage, the 'valve jwould drop to close the port 368 and to open atmosphere port 362 thereby admitting latmosphere to tho interior of pneumatic 365i;

It it'sde'sired to place the apparatus for `increasing the normal minimiun degree of high 'exliaustunder the oontrolof the music sheet. ai valve'rnechanism, tracker 4 vent, and duct, may be provided to place the pneumaticv 364 in communication with exhaust vwhenever the controlling trackerl vent is open. .fl`,l,1:is may conveniently be accomplished herein. by means of theduct 376 opcning,.to the diaphragm chamber 373. Assuming that. the slide valve 3711v is closed, the valve 371 maybe operated by the admss i of atmosphere through tracker duct ltfiand the. pneumatic 364y is then. placed iizicoinmunication vwith regulated exhaust .elicit l2. Vflhereafter if the .degree of regulated lexhaust approximates [theA degree-cf high' exhaust .the'pneumatic'.will be operated as heretoforedescribed,

It;V is bto be. understood that the invention Us andde'scribed above for in the scope obtlicgsubjoined claims, i,

l claim as my invention;

y l.. In an instrument.ofnhewcharacter describedland having playing 'plieumatic's, a Amain..sor-ir ce .of power for operating said pneumaticsnand regulating xneiinsv interposed therebetween; governor .bellows operatively connected to said. main V source of power; resilient Vmeans tendingtolhold said bellows lin ,expanded position an .atmosphere poi-tito said bellowsl;..means..to'o enisaid portl when a predetermineddegree o exhaust has lbeen established in said 1bellows;-'and means responsive to variations in'regulated tension for delaying the :effectives ening of said port until a higher -de ';o4 exhaust hasibeen established in-saidlelows;

2. In an instrunentof thefcharacter described'andfhaving. playing pneumatics; a. main source of power ,forfoperatng said pneumatics and regulatingV means'4 interposed therebetweemfa governorl bellows opera.- tivcly connected to said 'main source of power; ,resilient means tending to hold said bellfowsin expanded position; an'atmos here port to Asaid bellows; meanst'o'o'pen sai port whena predetermined de ree of exhaust has been established in said ellows; and automatically operable means responsive to variations in regulated tension fordelaying the reflective opening of said port until a greater 'degree of tension has been established in said bellows.4 y

3. ln an instrument of the character described and having playing pneumatics, a

main source of powerfor operating said pneumatics and regulating means interposed therebetween; a governor bellows operatively connected to said main source of --power; resilient means tending to hold said :bellows in expanded position; an atmosphere lport to said bellows; means toopen 4said port when a, predetermined degree of exhaust has been established in said bellows; a tracker; tracker `controllable means normally responsive to variations in regulated tension for :delaying the effective opening of said f ort until a Agreater=-degree of tension has 1 een established in Ysaid bellows. .A

4. In an instrument of the character de` scribed and` having playing pneumatics, a main source of power for operating said pneumatics and regulating meansinterposed therebetween; a governor bellows operatiyely onnected to saidmaimsource or power; resilient means tending to hold said .bellows in expanded position an atmosphere port. toisaid bellows; a valve for said port; means to 'open said valveupon collapsev of governorybellowslpand means responsive toA variations in regulated tension for changing the position of said valve opening means relatively to the movable board of saidl Governor bellows.l,...

n Van instrument of the character de- ,scrbedgandhaving .playing pneumatics, a 'main source of power for operatingsaid pneumatics and regulating means interposed therebetween; a .governor bellows operatively connected to said main source of power; resilient means tending to hold said bellows in expanded position; an atmosphere port towsaid bellows;,a valve for said port; means to-opensaid valve upon collapse of said governor licll0ws;; .and automatic means responsive to variations inregulate'd tension for changing the position of said valve opening means relatively to the movable board of said governor bellows.

A 6. In: an instrument of the character described and having playing pneumatics, a main source of power for operating said pneumatics and regulating means interposed therebetween; a governor bellowsopera tivelyl connected to said main source ofl power; resilient 'means tending to hold said bellows iriexpanded position; an atmosphere port to said bellows; a valve for said port; means to open said 4valve upon collapse of said governor bellows; and manually controllable moans normallyr responsive to variations in regulated tension for changing the position of said valve opening means relatively to the movable board of said governor bellows. A

7. In an instrument of the character described and having playing pneumatics, a main source of vpower for operating said pneumatics and regulating means interposed therebetween; a governor bellows operativelyl connected to said main source of power; resilient meanstending to hold said bellows in expanded position; an atmosphere ,portito saidbellows; a valve for said port;

tneansjto open said valve upon collapse of `jsa lv Tgovernor bellows; a' tracker; v and 'traekerzcontrollable means normally .responsive"to' variations in regulatedvtenslon for chan ng the' position ,of said valve: openrof rneans relatively tothe movableboard 're'slie'ntineans tending to hold said bellows 'inex andedfposition; laniatm'os'ph'ere port @f5 'vlve opening mans'frelatively to the movffl "9. "In janfi'nstrnment of v'the character des'cribe'dfand having playing Vpnenilmatics,' a main source o f powen/for,operatingsaid 30 pnenma'ti'cs'and vregulating means interposed y35 to sard bellows; a valvefor said port; means 'toopen said-valve upon collapse of .said V-govejnor bellows and manu ally controllable pneumatic Vmeans .normally responsive 4to -variations in regulated tension `for chang- '40- in the position of saidvalve o ening means re atiif'ely to: the movable boar of said gov- ,ernor'b'elllows x10.I`n' an instrument, of the character described and having playing pnenmatics,

y a main source offpower for 1operating'said i Y `Tpneumatics yand regulating means interposed i therebetween; a governorbellows -with relatively' movable walls operatively connected 1 to s aid main source of power; an atmosphere 5o/port inone otsaid walls; ,a valve for said i port; 4means operatively related to the other y )vallffor'opening said valve; and means res 'sponsive to variations'in regulated tension for changing the relationo' said valve open- Ving means to said atmosphere port.

,'11..ln an instrument ofV the character described and liavingplaying pneumatics` la main source of: power'for operating said pneumatics and regulating means interposed 460 `4tpherebetWeen; a governor bellows with relatiyfely movable walls operatively connected l to said main source of power; anatmospliere portjin one of said walls; a valvefor said port; means' operatively related to the other wall for opening said valve; and Pneumatic means responsive to'variations in regulated tension for changing the relation of said valve opening means to said atmosphere port.

12. In an instrument of the character described and' having playing pneumatics, a main sonrceof Vpower for operating said pneumatics and regulating means interposed therebetween; a'governor bellows with relatively movable Walls operatively connected Ato said main source of power; an atmosphere port in one of said walls; a valve for said port; means operatively related toA tbe other wall for opening said valve; and automatic pneumatic, means responsive to varia-tions in 'regulated tension for changing the relation of sa'idvalve opening means to said atmos- `plier-e ort.

13.- n "an instrument of the character "described i.and having playing pneumatics, a main 4source 4of poweror operating said pneumaties andl regulating means interposed the'reluetvvee.;4 @governor bellows with relatively movable vwalls'(.Jperz'itively connected Lto saidmain sonrce'of power; anatmosphere lport in one of said A'walls;.a valve for said port; means operatively related to the other wall for opening said' valve; and manually controllable Lpneumatiomeans normally responsive to variations in regulated'tension for changing the relation of said valve opening meansito said atmosphere port.

A lln an instrument of the character rdescribed" and"having playing pneumatics; Q 'a main `sourcecnf power for operating vsaid pneumatics and regulating meansV interposed therebetween "'g'a overnor bellows vvith rela- '.tiv'ely .movable `Walls operatively connected tosal'd main source of power; an atmosphere port in one -'of said walls; a valve for said l port; means'operatively related to the other wa'll'for opening saidvalve; and manually controllable means normally responsive -to variations in regulated tension for changing fthe `.relation ofsaid valve opening means to said. atmosphere.' port.

l5. I n an instrument of v,the character described Vand "having playing pnenmatics, a main source o' power for operatingsaid pnenm'ajtics and regulating means interposed 1- thereb'e'twoen; a governor bellows with relatively movable walls operatively connected to said main source of power; an atmosphere .lport'ginone ofsaid walls; a valve for said v 'po`;rt;v means loperatively'related to the other ivall'nfor openin i said valve; a tracker; and tracker control able means normally responsive to variations in regulated tension ,for changing the relation of said valve opening meansfto said Yatrioospherel port.

16. 'In :an instrument of fthe character described and having playing pneumatics, a main source of powerior operatingv said pnenrnatics and regulating means interposed thelebetween; a` governor bellows operatively connected to said main source of power Vll5 and including, a movable board, resilient means tending'to hold4 said bellows in expanded position, an atmosphere port in said movable board, a valve `for said port mounted upon a valve stem, an abutment for the valve stem mounted upon the fixed board and means to change thepositi'on of Said abutment to vary the operation: of the governor bellows. f

17. In an instrument of the character describedand having playing pneumatics, a main source of power for operating said pneumatics and: regulating'meansinterposed therebetween; a governor bellows operatively connectedl to said `main sourceof power and including, amovable board, resilient means tending to hold said bellows in expanded position, an atmos here ort in said lmovable board','a ,valve` or said port mounted upon a valve stem', aniabutment vfor the valve stem: montedjponthe fixed board, and 'automaticpneumatic means to change the position of'saidabutnient to vary the operationfof thefgovernor bellows.'

18. In'an Iinstriiinentof the character described and havingpl'aying" ='pneumatics,` a main source" of power forfoperating' said pneumatics and regulating nie'ans'nterposed therebetween a governor bellbv'vsf operaltively: connected? to said" main soilrce" of power' and "including, fafinvable board, resilient means tending to; holdsaidf"bellows in expanded position, 'an ritmos vhere port lin said movable boadgarval've nbr-"said port mounted upon a valvesteiii, anabut'mentifor the valve stein muntedn'bn-the Afined board, and inanuallyfcont'o ed-*means 'to change the' position of'sad'abutmenttovary :the operation o'the'5gove'rnor bellows. 4 0

19. In an f instrunent'jo'f the` character described -and having playing pneumatica," a main source f power ff 'opraltin'l said pneumatics andnre'guliiting 4tiie'aiisfihte'l'pos'ed therebetween a'f governorj' bellowsj Yoperatively connected to s aidfrxaiii` source' of power and including, fa' rnova'blef'bord, resilient means tending 'toi hold; said bell'ows in expanded. position, an' Iatmosphere ,porti in said movable board,`a1valvefior'said port mounted upon a,valve'ste1n,`an abutment for the valve stem mounted""iron-f` the""`xed board, and manually control edfpn'enxnatic means to change the, position'bfisaid abutment to vary the'opera'tionfbf the 'governor bellows. "Y 'i 20. In an instrument offthe eharacterdescribed and having playing' pneumatics, a main source of power for operating said pneumatics and ,regulating means interposed therebetween; a governor bellows operatively connected to said mainsource of power and including, a movable board, resilient means tending to hold said bellows in expanded position, an atmosphere Vport in said movable board, a valve'rfor said port mounted upon a valve stem, an abutment for the valve stem mounted'upon the lixerl board, a tracker, andtracker' controlled meanstol chan e the position of said abutf mentto vary t bellows.` i 1. l 21. Inf'an` instrument of the? character described Vand/having playing pneumatics, :a main source of power for operating said pneum atics and regulating means interposed therebetween; a governor bellows operatively connected to said main source of power 4and including, a movable board, resilient means tending to hold said bellows in expanded position, an atmosphere port in said movable board, ay valve for said port mounted'uponE a valve stem, anabutment for the valve stem mounted upon the fixed board, and pneumatic 'means to change the Aposition of said abutment `to 4vary the voperavtion of thei'governoifbellowsgf 22. In an instrument of the character Adescribed' and vhaving-playing pneumatics',za 'mainsource Vofepowervfor operating said -pneumatics amd* regulating means interposed i therebetween; ba: lgovernor" fbellws operatively connected tosaid main= source 4of power 'and including, a.; movable board, .resilient means tending to hold said bellows e operation of the governor 'in expanded position, anfatmosphere port Ato "i5 saidl bellows,E "a valve .inf said port, c a: `valve stem extending into said reservoir bellows, a pneumatic 4withinfsad governor bellows having its movable boardin the path of said valverstem, and vmeans to introduce exhaust tolsaid pneumatic tovary the po'sitionoits :movable board'and' thereby vary the operation of said governor :bell'ows:v

\ 23.. In an 1mstrumentfof 1the character described and Ahaving. playing l`pneumatios,V a

main sourceI fof' power 'rfor' operating said pneumativcs and) regulatingmeans interposed -therebetween ;1 a.i f rgovernor i bellows opera- 'tively'connected:I to 'said mainj sourcetof resilient'me'ans f tending ibo i'hold l'said' bellows t in erp'an'ded position, an I atmosphere? port to 'saidfbellows a-valve i-n'vsaid port', ai valve `stem extending into` said'I reservoir bellows,

a" pneumatic withinfsaid 'governor' bellows1 -therebyvary the'operation of saidfgovernor4 bellows.` 4 f '24,ln an instrumentof the eharacterdescribedl and having iplaying pneumatics., a main sourcefof'ipower` foroperating said pneum atics and regulatingmeans interposed' therebetween; a' governor bellows opera- 'tivelyy connected `to said main4 source-of power and f including, a movable"I board, resilient means tending to hold saidbellows power and including, a movable boad,=

in expanded position, an atmosphere port to"-I30 A01 chest. and Isaid 1high said bellows, a `valve in saidport, a ,valve stem extendinggintofsaid reservoir bellows, .a pneumatic within .said .governor bellows having -ts movable board n-thepath ot said 5 valve. stem7 .and manually controllemeans to introduce exhaust to said pneumatic yto -uary-.the position of 'ts Imovable .board and .thereby .vary the operation .of -Saidngovernor bellows.

25.' In an instrumento the character describedand having playing pneumatics, a mainsource of power-for operating-said ,pneumatics and rcguletingameans interposed therehetvif-een;L a governor :'bellows oper- .'aLtiuely-vcolinected to .said main source of vpower/.anti iincluding, 4a movable4 board, resilient means-tending to .hold said bellows `in .expanded npositon, .'.an 4atmosphere port to) Seidl bellowsa valve-inzsnd port, a valve steluiexten'dxing i sidf reservoir bellows, a pneumatic within-said'. governor bellows -haviug-itsicmovableiboard Lin' theop'athl of .said`valve.;st em, a. tracker,V and tracker controlled. means to introduce .exhaust .tor said pneumatic-.to .vary the position .of its. movable-hoard. and thereby vary the operation 'of snidigovernor bellows.

`-126. Ali instrument of the character described 'comprising in combination, -.playing-g 30 Ipn'eunjlalims";= .ai main source eoperatngisaid playing -pneumatics -a valve betrifleen 'isaid main 2 source ofc. power and a freg'ilated .wndchest connectedto said plaviing pneumatics; means operatively connect- 35..ed to.said..main` source of -power for `nornialliy naintaining 'substantial uniformity -off.pressureutheren;. -means .connected to said valve for maintaining unor-niity of pressure inl-.said regulated -wnd chest at prede- 40 :teminedfileuelsgnand means operatively oon- "nected .withsad regulated windchestto vaiv theqlegree ofexhaust of the main. source of power upon-theestablishment of a prede- 'ftermned pressure in the' regulated wind chest.

.27. An. instrument of -the character de zseribeducomprising, in combination, playing pheumat1cs; amaln source of power for .operatingl .said playing pneumatics; means 5.0 -forlmantaining 'a substantially uniform ipressureat'theman sourceof power; a regu- :lated wind-.chest connected to .said playing Ilpneunaties.3- meansv controlling communica Vtienibetvv'eensaid mainsource .of power and said' regulated wind chest having' the capacity of varying the degree of pressure in said `regulated wind chest and ymaintaining any .einen pressure therein.; means, operatively connected' with said regulated .wind

exhaust pressure maintainingmeans to increase the normal .pressure-at--the.main source of power .whenever .the degree-of regulated pressure approximates that of -high exhaust.

- f,65- r aAnlnstnument of :thea character deof power =for ,scribed comprising, in combination7 playingjY pucuuiatics; a, main source of power for ,operating saidplaying pueumatics; expression governing mechanism operatively interliosed between said main source of power ,and the playing pneumatics to varyplaying i.ntensities; n1ean s to maintain a substantially ,uniform'tension at the main source of power; and means to increase the normal tension ,of the, main .sourceoli power when @he expression governing means *endete increase playing 'inl'.ensitiesto; approximate can intensity @terminaba ima the .normal .iensiouof :the:main..sourceppurger.,V

29. in instlullrnezjlt of theaqhmljale'r described comprising. immunisation" Pleying Pneumaties; av mal-n Slow-'ee Qi freue. O'I' .i-peratingisaid ,playing-.p ueuni tics; means wainanlminra substantially-sui emmer-mill pressylrenalnth mein :seance ai @Guerrer- :presslen comming; Omnium-:interiwsedllietneenslnemea.eeureavfinevrand -Ifhe playing! pneumatiss ierraryfee plenas intensities front-a predetermined@ mlamwn to. a .inanimu m depen dent :upon: the norm al pressure. ,of the, ,main ,source of power; land .lneansto vary `the .normal pressure. of the in ein ,source of Z power 4.for further .ual-.ying playingintensities. 30. .An instuurnr t of the character-de- .,Swibd .aneurisma inf-.Cembmen playing .plieumztties; .',a main' sourcelof ,power for operating said..,playing neumatlcs; ,means Ito maintain ,a. substantially.,uni:form no Y[unal A.pressure at the inainsource of. poirier; Vexpression ,governing-means operatively interposed .between the -maing'source oimowerand the playing. pneumaties forvfarying playing intensities from .a predetenrnined'mlnimum to a4 maximum; dependent-=upqn the no rmal` pressureof the. rrnain source. .ofi power; ,and 'automa tic. meansfto vary the normal I pres sure of the main source. of porver forfurther varyin g. playin g intensitiesl 3l. An instrumentof the character (lescribecleomprising, in combination, playing pnenma.t1cs; a mam Vsource ofpower for operating Y sald playin g ,pneluna-tlcs g t,means to maintain a Substantielly.l .uniform normal pressure atthe malinsourceof power; expression governing; A.meieuis .operatively .in terposed .between the .main source. of porter and the. playing pneumaticsfor automatic- .alllyvxarying .playing intensities. from apredetermined minimum to a4 maximumdepeudcnt upon thenormal pressure of thennaiu 4source of power.; .and .means Ato vary the lnormal pressure of themain source of power A for further.: varying playing intensities. f

32. An .instrument of the. cliarafzter.v described comprising,l in combination, playinkgr ,pneumatics; ,a main source of power for operatingsalid .playing .pneumatics g ...means .13o-maintain a sujlostantially uniform normal 1Apressure abthemain source ofpower; ex-

pression governing means operatively interposed between the main source of power and the playing pneumatics for automatically varying playing intensities from a predetermined minimum to a maximum dependent upon the normal pressure of the main source of power; and automatic pneu matic means to vary the normal pressure of the main source of power for further varying playing intensities.

33. An lnstrument of the character described comprising, in combination, pla-ying pneumatics; a main source of power for operating said playing pncumatics; a regulated wind chest; means to connect the )laying (pneumatics selectively to said regulated win chest; a high exhaust wind chest; regulating means operativelyA interposed between said wind chests; means to maintain a normal uniform pressure in the high exhaust wind chests; and Vmeans operatively connected with the regulated exhaust wind chest to increase the tension of high exhaust when the tension of regulated exhaust approximates the tension of the normal high exhaust and thereafter further increase the tension of regulated' exhaust.

34. An instrume-nt of the character described comprising7 in combination, playing pneumatics; a main source of power for operating said playing pneumatics; expression regulating and varying means interposed between the main source of power and the playing pneiunatics; and supplementary expression varying means actmg upon said main source of power;

35. An instrument of the character described comprising, in combination, playing pneumatics; a mainisource of.` power for operating saidplaying pneumatics; andA two expression governing means,one opera-tivelyY interposed between the main source of` power and the playing pneumatics, and the other adapted to vary the pressure of the main sourceof power.

36. An instrument of the character described comprising,l in combination, playing pneumatics; a regulated wind chest forsaid playing pneumatics; a main source of power for operating said playingY pneumatics; ex` pression governing and varyingimeans operatively interposed between said. main source of power and said regulated wind chest; menus for normally maintaining a uniform pressure at said main source of power; means for varying the pressure at said main source of power; and manually controlled mea ns to connect said last named means with said regulatedwind chest.

37. An instrument of the character described comprising, in combination, playing pneumatics;a regulated wind chestfor said playing pneumatics; a main source of power for operating said playing pneumatics; ex-

pression governing and varying means oper- :gra

atively interposed betweenpsaid main source of power and 'said regula-ted wind chest; means for normally maintaining a uniform pressure at said main source of power; pneumatie means for varying the pressure at said main source of power; and manually controlled means to connect said lastfnaniczl means with said regulated wind chest. Y

38. .An instrument of thechara'cter described comprising,l inI combination, laying pneumatics; a regulated wind chest or said playing pneumatics; a main source of power for operating said playing pneumatics; expression governing andvarying-means operatively interposed between said main source of power and said regulated wind chest'; means for normally maintaining a uniform pressure at said main source of power; automatic pneumatic means for varying the pressure at( said main source ofpowezgand4 manually controlled means tofconnect s'aidlast named means with said regulated wind chest. A i y 39,.An instrument of thecharacter de scribed comprising,in combination, playing pneumatics; a4 regulated wind chest for said pla ingpneumatics; a main source of power or ,operating saidp1a'ying pneuvmatics; expression governing and varying means doperativelyl interposed between' saidv main sourceiofjpower and said regulated windchest; a, governor bellowsT o -)eratively connected to said i:main source of power; means 'for tensioning vsaid governor bellows; means to maintainsaidtension substantially uniform pneumatic means, to vary said tension to vary the degree ofpressure at said mainfgsource of power;.`and manually controlled means toconriect Said last namedl meanswi-th said 4regulatedwind chest.. y

40..An, instrument of. the. character ,def scribed comprising, in lcombination, playing pneumatics; a regulatedfwind 4chest for. said playing pneumatics; a main source of power for operating said playing ,pneumatics;ex pression governing and varying means operatively interposed between .said main source of power and said regulated wind chest; a governor bellows operatively connected to said'main source of power; resilient means tending to hold said bellows in expanded position; 4means providingl an atmosphere port to said bellows; means tol open said port, when. a predetermined degree of exhaust has been established insaid bellows; pneumatic means to delay the effective opening of said port until ahi vher :degree of exhaust has been establishe in said bellows; andlmanually controlled-means to connect said last named means with said regulated wind chest. A

41. An instrument of the character described comprising, in combination, laying pneumatics; a regulated wndchest or said playing pneumatics; a lmain source of wind chest; a` governor power for operating said playing' pneumatics; expression governing and varying means operatively interposed between said main source of power and said regulated bellows operatively connected to said main source of power; re- Vsilient means tending to hold said bellows in expanded position; means providing an atmosphere lportto said bellows; a valve for said port; means to opensaid valve upon collapse of saidgovernor bellows; pneumatic means to change' the position of said valve opening means relatively to the movable boa-rd ofs'aid governor bellows; and manually controlled means to connect said Iastnamedmeans with said regulated wind chest.

42. A11 instrument of thev character described comprising, in combination, playing pneumatics; a regulated wind chest for said playinsrnsletmse nevi. Savia@ i0? reve" for operat'rigsad' pIaymgpn-unancs; expression governing and varying means operatively interposed between' said main .source tso 'sill of power 'and .s'aid regulated windehest; a governor bellows with relatively movable walls operatively connected to ,said main source of power;` means Aproviding an atmosp'heiport in' one 4of said walls; a valve for 4said. port; means'ope'ratively related to the'other wall'jfo'r opening said valve; pneumatic means to vary' the relation of said valve' opening' means' tb said' atmosphere port; and manually controlled means to conl35 nect saidlast named means with said regulated wind chest;

43. An, instrument of the character described 4 comprising, in combination, playin pneiatlcs; a regulated wind Chest for said playing pneumatics; a main source ol" power or ,operating said playing pneumatics; e'rpressionl governing and varying means operatively interposed between said main so'uice of power and said regulated windchest; a governor bellowsfoperatively conlectedto said main source' of power and including, a' movable board, resilient means tending to hold 'said bellows in expanded position, means providing an atmosphere port infsad movable boarda valve for said port miln'tedupon a. 'valve stexn'; an abutment mpuntedf upon a fixed boardg-,pneumatic me'ansto change the position of'said abutnenttovarv the"peration of the governor bellows; and manually controlled means to connect 'Said 'last n atned' means with said regulated-,wind chest.

"Ml-n vinstrumenty o*f the character described comprising," in Ecoin-bination, playing pneum`atics";'argu'late'rl wind'c'hest for said laying pneumati'cs; a main source' of power di" dsai'd playdngfpneuma'tics; express en 'overriirgiand varyingmeans opertively in erposed'between'ssid' mafia source' df power andsaid regnlalfedlvfind chestga governor bellows operatively connected to said main source of power and including, a movable board, resilient means tending to hold said bellows in expanded position, means providing an atmosphere port in said movable board, a valve for said port; a valve stem extending into said governor bellows; a pneumatic within said `governor bellows having its movable board in the path of said valve stem; and manually controlled means to introduce regulated exhaust' to said neumatic to vary'the'pdsition o'f its mova le board and thereby vary the operation of said governorbellows.

45. An instrument of the character de'- scribed comprising, in combination, layi'n pneumatics; 'zr-regulatedwin-'d chestr or said playing pneumatics; a' 'Inainsource of-power for operating'said plavng neumatics; expresslon governin'g'an varym means oper-" atii-*ely i'nterposedbetween 1saf main source of power and sad regulatedwind chest; means Y for Vnornflally'Ilai'itairig Ia Euniform pressure' at said :main source' of pover; mea nsfor 'varying' the 'pressure at said main source of'povver'; a tracker; and tracker controlled means to'vco'n'nect s'aida last named means with said regulatediwindches't, i

46. An instrument O "the chabtelidei scribed comprising, incombinatien, 'laying pneumaticsg'a' regulate'tlwind chies't Vor said playing pneuma-tlcs; a :nain source otfp'owe for operatngisaid playngpeumaticsf; eX- pression governinlgand varyingmeans o'peratively interposed betweeny 'said main source of power and S'iai'di regulated 'Wind chest;` means for' normallynraintaining a uniform i pressure at saidt main sourc'e'of power; pneumatic' meansV for' varying'the pressure atV saidfmainsonrce of power; a tracker; and tracker controlled means to connect said last: named means with said regulated wind-chest.v

47. An instrur'nent of the character described comprising, in combination; laying pneurnaties; 'a regulsrted Wind'cliest or said playing pneumatic's'; a main Vsource of power for operating said playing pneumatics; cxpression governing andvaiyingmeans operatively interposed between" said main source of power aind said' regi'ilated wind chest; means fornori'nally maintaining a' uniform pressurel at saidv VVmain source of power; automatic pneu-"matic means for varym'g the pressure at' said main source of power; a tracker; and' tracker controlled means tol connect said last named means with said regula/ted wind chest;

48. An instrument of the character described comprising, in combination, laying pneumatics; a regulated wind chestV or said playing pneumatlcs; for operating said playing' pneumatics; eX- pressantl governing and varying Vmeans operatively interposed between said main afmain source of power' ics source of power and said regulated wind chest;' a governor bellows operatively connected to said mainsource of power; means for tensioning. said governor bellows;v means to maintain said tension substantially uniform; pneumatic means to vary said tension to vary the degree ofpressure at said main source o power; a tracker; and tracker controlled mea-ns to connect said last named means with said regulated wind chest.

L15).'An instrumentof the character dscribed comprising, in combination, playing pneumatics;'a regulated wind chest-for said playing pneumatics; a main source of power for operatingr said' playing pneumatics'; expression' governing and varying means operatively interposed between said main Source'of power and said regulatedwind chest; a governor bellows operatively connected tosaid main source ofpower;l resilient means tendingA to hold said bellows in'4 'expanded position; me'ans'providing'an atmosphere' port to Said bellows;`meansto open said portwhen a' predetermineddegree of exhaust has beenestablished' in said bellowsypneumatic meansto delayi'the effective openingofsaid 'porti until a higher degree `of exhaust has been'e'stabli'shed in said bellows; a tracker; Aandtracker 'oo ni trolle'cl `means "to connectsaid"last`fnamed means with said V'regulated`*wind 'chest i' l'50. An instrument' of thecharacter described comprising, in combination,v playing pneumatics; a'regulated' wind' chest for said playing pneumatics'; a lmainsource of power for operating said playingpneumatics;"ex pression *gevel-'ning' and varying" 'means-op-j eratively interposed fbetweenj' said* main source' of. power and said regulated "wind chest a 'governor 'bellows operati vely" con-1 nectedjt-o saidfm'ain" source of power; 'res sili'en't means'tendiIg-to hold Isaidjbellows in 'expe'nded"position': imeans '.p roviding' an atmosphere portto said bellows; a valve flor said port; means to open said valve upon collapse o'jsaid governor 'bellows;pn euf matic 'mea'nsto' cha-nge t-he position ofsaid valve opening means relatively to the'n'ov-l able' boardfof said governor bellows;` a tracker; and tracker controlled means to' connect said last named means with'said regu# lated'wind chest.' j

51. Andnstrument 'of the character de` scribed comprising, in combination, laying pneumatics; a regulated wind chest or'said playing pneumatics'; a main source of power for operatingr said playing pne'umatics;` ex'-4 pression governing and-"varying means operatively interposed between said main sourceV of power and said regulated wind chest; a governor bellows with relatively movable walls operatively connected to said main source'of power; means providing an atmosphere port in one of said walls; a valve for said port;4 means operatively relatedf to the other wall for opening said valve; pneumatic means to vary the relation of said valve opening means to said atmosphere port; -a tracker; and tracker controlled means to connect said last named means with said regulated wind chest.

52. AnV instrument o't' the character describedcomprising, in rombination, playing pneumatics; a' regulated wind chest for said playing pneumatics; a main-source of powei for 'operating said playing pneumatics; expression governing and varying means operatively interposed between said main source of power and said regulated windl chest; a governor bellows operatively con` nected 'to said main source of power and including, a movable board, resilient means tendingto hold said bellowslin expanded position, means providin an atmosphere port inl said movableboar a valve for said port mounted' upon a valve stem; an abutment mounted upon a fixed board, pneu`-` matic means Itochange' the position ot' said abutment to vary the operation of the governor bellows a tracker; and' tracker controlled means to connect said last. named means with said regulated wind chest;

'53."An instrument of 'the A:character described comprising, in combination, laying pneumatics; a regulated wind chest or said laying -pneumatics amain source of power $61 operating said playing'pneumatics; expression governing land varying"` means opnatively-"interposed between said main source ofp'ower and said'regulatecl wind chestr'g" Va governor bellows operatively lconnected to"s'aidmain source of power andincliiding, aimovable boardgfresilient means .tending t'o""h0ldL said bellows-in-expanded position, fmeans' providing an zatmosphere poit in''said-Inovav leV board, avalve for said port; aj'v'alv'e' stem extending into said gove'norgbelloyvs a4 pneumatic within said governoiibellows having its movable board in the path of saidvalve stem a tracker; and t'r'a'ck'er controlled meanstointroduce regulated'exhaust to said pneumatic to vary tbe p'osition of movable board and thereby vary 'the operation of said governor bellows-'V i if? i 'f o v54. An instrument of the character described'comprising, in combination, playing pn'eurnaties;v 'a mainrson'rce off'power for operating said' playing pneumatics; `a high exhanstwind chest communicating with said main source=of power; a regulated exhaust wincl-chestfcommunicating with said play! ingpnefurnatics; expression governingr and varyin means including a throttle valve controlpliinga port 'between said wind chests andadapted to be opened i'n the direction of the pressure otregulated exhaust; means io maintain a normallyuniform pressure of high exhaust; and means to vary said pressure to varyregulation by said throttle valve.

ioo

An instrument of the rliarnrter dcscribed -comprising, in combination, playing pneumatics; a main source of power for operating said playing pneumatics; a high exha-ust wind chest communicating with said main source of power; a regulated exhaust windchest communicating with said playing pneumatics; expressiongoverning and varying means including, a throttle valve controlling Va port between said wind chests and adapted to be opened in the direction of the pressure of regulated exhaust; means to maintain a normally uniform pressure of high exhaust;and means to increase the degree of exhaust at said main source of power to increase the forces tending to. open said throttle valve.

56.An instrument of the character describedcomprising, in combination, playing neumatics; -a main source of power for operating-.said playing pneumatics; -a high exhaust wind chest1 communicating with said main'source'of power; a regulated exhaust wind chest communicating with said playing neumatics; expression governing and vaaymg means including, a throttle valve controlling a port between said wind chests and adapted-'to be opened in the direction of'the'i pressi'rreof regulated exhaust; means for narmaillyimaintaining a uniform pressure at said main source of power; and pneumatic I'neansfor varyingthe pressure at said main source of power. i

57. Al-,instrument of the character described comprising, in combination, playing pneumatics; a main source of power for operating said playing pneumatics; a hi hexhaustA wind chest communicating wit said main-source of power; aire'gulated exhaust4 wind-chest communicating with said playing pneumatics; expression 4governing and varying. means including a throttle valve controlling a port between said ywind chests and adaptedfm be openedin the direction ot` the pressure of regulated exhaust;'means for normallymaintaininga uniform pressure at saidV mainsource of power; pneumatic means-'for varying the pressure at said main source of power; and manually controlled means to connect said last named means with said regulated wind chest.

58. An instrument of the character described comprising, in combination, playing pneumatics; a'main sourceofpowerfor operating said playing pneumatics; a high exhaust wind chest communicating with said main sourceof power;a regulated exhaust wind-chest communicating with said playing neumatcs; expression governing and varyin means including a throttle valve control ing' aport between lsaid wind'chests and adapted to be'opened in the direction of the pressure of regulated exhaust; means for normally maintaining a uniform pressu-rbat saidmainsource of power; pneumatic means lor varying-the pressure at said main source ot power; a tracker; and tracker controlled means to connect said last named means with said regulated wind chest.

59. An instrument of the character described comprising, in combination, playing pneumatics; a main source of power for operating said playing pneumatics; a high exhaust wind chest communicating with said main source of power. a regulated exhaust wind chest communicating with said playing pneumatics; expression governing and varying means including a throttle valve controlling a port between said wind chests and adapted tobe o the pressure of regu ated exhaust a governor bellows operatively connectedto said main source of power; means -for tensioning said governor bellows; 4means to maintain said tension substantially uniform; and means to vary. said tension to vary the degree of pressure at said mainso'urce of power.'

60. An instrument of the character described comprising, in combination, playing pneumatics; a maln source of power for operating said playing pneumatics; .a high exhaust wind chest communicating with said main sourceof power; a regulated exhaust wind chest communicating with said playing pneumatica; expression governing and varying means including a'l throttle valve controllin a port between said wind chests and adapte to be opened in the direction of the pressure of re lulated exhaust; a governor bellows operatively connected to said V4main source of power resilient means tending to hold said bellows. in expanded position; means providing an atmosphere port to said bellows; a valve for sai port; means to open said valve upon collapse of said governor bellows; and means to change the position of said valve opening means relatively to the movable board of said governor bellows.

61. An instument of the character described comprising, in combination, playing pneumatics; afmam source of power for operating said playing pneumatics; a high exhaust wind chest communicating with said main source of power; a regulated exhaust wind chest communicating with said playing pneumatics; expression governing and varying means includingA athrottle valve controlling a port between said wind chests and adapted to be opened in the direction of the pressure of regulated exhaust; a governor bellows operatively connected to said main source of power and including a movable board, resilient means tending to hold said bellows in expanded position, means providing an atmosphere port in said movable board, a valve for said port mounted uponl a valve stem; an abutment mounted upon a fixed board; and means to change the ned in the direction of position of said abutment to vary the operation of said governor bellows.

62. An instrument of the character described comprising, in combination, playing pneumatics; a main source of power for op.- erating said playing pneumatics; a high eX- haust wind chest communicating with said main source of power; a regulated wind chest communicating with said playing pneumatics; expression governing and varying means including a throttle valve controlling a port between said wind chests and adapted to be opened in the direction of the pressure of regulated exhaust; a governor bellows operatively connected to `said main source of power and including a movable board, resilient means tending to hold said bellows in expanded position, means providing an atmosphere port in said movable board, a valve for said port mounted upon a valve stem; an abutment mounted upon a fixed board; and pneumatic means to change the position of said abutment to vary the operation of said governor bellows.

63. An instrument of the character described comprising, in combination, playing pneumatica; a main source of power for operating said playing pneumatics; a high exhaust wind chest communicating with said main source of power; a regulated wind chest communicating with said playing pneumatics; expression governing and varying means including a throttle valve controlling a port between said wind chests and adapted to be opened in the direction of the pressure of regulated exhaust; a governor bellows operatively connected to said main source of power and including a movable board, resilient means tending to hold said bellows in expanded position, means providing an atmosphere port in said movable board, a valve for said port mounted upon a valve stem; an abutment mounted upon a fixed board; pneumatic means to change the position of said abutment to vary the operation of said governor bellows; and manually controlled means to connect said last named means with said regulated wind chest.

Y64. An instrument of the character described eomprising, in combination, playing pneumatics; a main source of power for operating said playing pneumatics; a high exhaust wind chest communicating with said main source of power; a regulated wind chest communicating with said playing pneumatics; expression governing and varying means including a throttle valve controlling a port between said wind chests and adapted to be opened in the direction of the pressure of re ulated exhaust; a governor bellows operatively connected to said main source of power and including a movable board, resilient means tending to hold said bellows in expanded position, means providing an atmosphere port in said movable board, a valve for said port mounted upon a valve stem; an abutment mounted upon a fixed board; pneumatic means to change the position of said abutment to vary the operation of said governor bellows; a tracker; and tracker controlled means to connect said last named means with said regulated wind chest.

In testimony whereof, I have signed my name to this specification this 28th day of March, 1917.

CHARLES F. STODDARD. 

